66 



HIGH SCHOOL ZOOLOGY. 



recognized, the Percina (including the common perch \Perca 

 americana] and the larger Pike- Perches or Pickerels [Stizosted- 

 ium] as they are generally called in Ontario, and the Etheostom- 

 atina or Darters. The pickerels attain a greater size than the 

 perch, and are valued food-fishes. The larger species, S. vitreum 

 has three pyloric coeca, its fin formula is D.XIII — I, 21; A.II, 12, 

 while the smaller JS. canadense (Fig. 34) has 4-7 coeca, and the 

 soft dorsal is shorter by three rays. Like the perch the picker- 

 els have a good deal of brilliant yellow colouring on the sides 

 and are called " dorees " in the Lower Province. 



.A.^^ 



Fig. 34.— The Pickerel. Stizostedium canadense. \. 

 (U. S. F. C.) 



19. Little is known with regard to the distribution of the 

 Darters in Ontario. They are a characteristic American group, 

 being amongst the smallest of the Fishes, and distinguished 

 further by their bright colours, rapid movements, large fins, 

 and the rudimentary condition of the pseudobranchs and air- 

 bladder. Some of them conceal themselves under sand, the eyes 

 alone remaining uncovered, the better to pounce rapidly upon 

 the active insect larvae on which they feed. The largest of the 

 group, the Log-Perch {Percina caprodes), attains a length of 

 6-8 inches, and may be recognized by its black, banded sides, 

 the smaller forms are the Sand-dartei (Ammocrypta), Tesselated 

 darter (Boleosoma ) and the Striped darter (Etheostoma). _ 



20. Among the marine tannlies allied to the above that of 

 the Serranidse requires mention. It embraces the so called Sea- 



